Gold Member Badge


  • You're all caught up!

The Average Length and Weight of Newborns

author image Sara Ipatenco
Sara Ipatenco has taught writing, health and nutrition. She started writing in 2007 and has been published in Teaching Tolerance magazine. Ipatenco holds a bachelor's degree and a master's degree in education, both from the University of Denver.
The Average Length and Weight of Newborns
A close-up of a medical practitioner measuring a newborn baby. Photo Credit: sumerphotography/iStock/Getty Images

The weight and length of a newborn baby is among the most sought-after information when loved ones hear the news that a little one has been born. While it's enjoyable to hear these vital statistics, weight and length are measured because they are valuable predictors about a newborn's health, and they also provide a suspected growth pattern to pediatricians. Keep in mind that averages indicate the most common weights and lengths for babies, and your baby might fall outside of these averages and still be completely healthy.

Video of the Day

The Long and Short of It

Babies delivered at the standard 40-week mark measure an average of 20.16 inches long, according to A baby born at 41 weeks gestation measures an average of 20.35 inches. A baby delivered between 38 and 39 weeks measures an average of between 19.61 inches and 19.96 inches. Of course, babies who are born prematurely tend to be smaller in length than babies who are born full-term.

Does Length Matter?

Being shorter or longer than the average length doesn't necessarily indicate a problem. In fact, the height of the baby's parents can play a role in how long a baby is at birth, so very tall parents might have a baby longer than the average, while shorter parents might have a baby that's smaller than the average, according to Concern for a smaller-than-average baby can come into play in the case of premature births, however.

A Weighty Issue

Most babies born at 40 weeks gestation weigh an average of 7.63 pounds, according to A baby who isn't born until 41 weeks gestation weighs an average of 7.93 pounds, and one who makes it to 42 weeks gestation weighs an average of 8.12 pounds. A baby born at 38 weeks, on the other hand, weighs an average of 6.8 pounds, notes. The averages are smaller for babies who are born prematurely.

What Does It Mean?

While there isn't as much concern when a baby is shorter or longer than average, being much lighter or much heavier is a cause for concern in many cases. According to the Lucile Packard Children's Hospital at Stanford, a baby who is small for her gestational age is at a greater risk for oxygen deficiencies, low blood sugar, a higher than normal red blood cell count and difficulty maintaining body temperature. Babies who are born much larger than average are at risk for low blood sugar and injury during the birthing process, according to the National Institutes of Health's MedlinePlus.

LiveStrong Calorie Tracker
Lose Weight. Feel Great! Change your life with MyPlate by LIVESTRONG.COM
  • Gain 2 pounds per week
  • Gain 1.5 pounds per week
  • Gain 1 pound per week
  • Gain 0.5 pound per week
  • Maintain my current weight
  • Lose 0.5 pound per week
  • Lose 1 pound per week
  • Lose 1.5 pounds per week
  • Lose 2 pounds per week
  • Female
  • Male
ft. in.


Demand Media